刘展 刘亚丽 余兵

[摘要]目的：应用锥形束CT（Cone beam computed tomography，CBCT）评估无托槽隐形矫治压低上颌伸长磨牙的矫治效果和牙根吸收情况。方法：选取20例在无托槽隐形矫治过程中有压低上颌伸长磨牙的成年患者（其中18颗上颌第一磨牙，12颗上颌第二磨牙），收集患者压低治疗前后的CBCT，测量伸长磨牙的压低效果和牙根吸收情况。结果：30颗伸长磨牙均有效压低，压低治疗时间平均8.2个月。18颗第一磨牙和12颗第二磨牙相对于基准平面平均压低2.12mm（P<0.001）和 1.32mm（P<0.001）。压低前后伸长磨牙在近远中和颊舌向的倾角变化不明显。治疗后有7颗磨牙发生轻度牙根吸收，1颗磨牙发生中度牙根吸收。结论：隐形矯治能有效压低伸长磨牙，牙根吸收情况较轻。

[关键词]无托槽隐形矫治;压低;伸长磨牙;牙根吸收;锥形束CT

[中图分类号]R783.5    [文献标志码]A    [文章编号]1008-6455（2021）05-0119-04

CBCT Evaluation of the Clinical Efficacy of Clear Aligner on Overerupted Maxillary Molars Intrusion

LIU Zhan， LIU Ya-li， YU Bing

（Department of Orthodontics， Affiliated Dental Hospital of Kunming Medical University，Kunming 650000，Yunnan，China）

Abstract： Objective  To evaluate the clinical efficacy of clear aligner on overerupted maxillary molars intrusion by CBCT. Methods 20 adult patients （including 18 maxillary first molars and 12 maxillary second molars） who had intruded overerupted maxillary molars in the clear aligner treatment. The effect of intrusion and root resorption were observed by CBCT images before and after the treatment. Results The 30 overerupted molars were all effectively intruded. The average treatment period was 8.2 months. Intrusion distance relative to the palatal plane were 2.12mm（P<0.001） and 1.32mm（P<0.001） for the overerupted upper first molars and upper second molars. There was no significant change in the mesiodistal tipping and buccolingual tipping. 7 molars had mild root resorption and 1 molars had moderate root resorption after the treatment. Conclusion  Clear aligner treatment can effectively intrude the overerupted maxillary molars， and the root resorption is light.

Key words： clear aligner treatment; intrusion; overerupted molars; root resorption; cone beam computed tomography

下颌磨牙长期缺失，未及时进行有效的修复，可导致上颌磨牙过度伸长，严重影响患者的生活质量。因此，对上颌伸长磨牙患者进行压低治疗具有重要意义。截冠术、片段弓技术是临床上的传统治疗手段，但其具有牙损伤、邻牙支抗丧失等缺点[1]。近年来微种植体的使用日益广泛，其压低伸长磨牙的效果肯定[2-3]，但存在损伤牙根、松动脱落及穿透到上颌窦等风险[4-5]。1998年，无托槽隐形矫治技术问世，由于其美观舒适，便于清洁，椅旁操作时间短，复诊间隔时间长等优势，越来越受患者和医生的青睐。无托槽隐形矫治器能同时在唇舌侧包绕伸长磨牙的牙冠，施加的力可通过磨牙的阻抗中心[6]，理论上对磨牙的压低方向有更好的控制。本文通过临床研究对无托槽隐形矫治技术压低伸长磨牙的矫治效果和牙根吸收情况进行观察，以期为正畸临床提供帮助。……